The management and treatment of a wound, a surgical site, a surgical incision, or otherwise infection-prone tissues in the body, has three primary objectives: (1) prevention of infection, (2) preservation and/or restoration of function, and (3) preservation and/or restoration of cosmetic appearance. The most important of these objectives is the prevention of infection. Success in the prevention of infection directly affects the healing process and the degree to which function and cosmetic appearance can be preserved and/or restored.
The number and virulence of bacteria present at a site are critical determinants of whether the site becomes infected. Experimental evidence suggests that a critical level of bacteria is approximately 105 organisms per gram of tissue. Below this level, a site or a tissue typically heals; at levels greater than 105 bacteria per gram of tissue, infections often develop. Dirty wounds, or wounds that have not been treated within six hours, are likely to be contaminated with bacteria at levels that are higher than the critical level. Reducing the number of bacteria in and around the wound is critical for avoiding infection and expediting wound healing.
Methicillin-resistant Staphylococcus aureus (MRSA) infection is caused by Staphylococcus aureus bacteria—often called “staph.” Decades ago, strains of staph emerged in hospitals that were resistant to the broad-spectrum antibiotics commonly used to treat them. These antibiotics include methicillin and other more common antibiotics such as oxacillin, penicillin, and amoxicillin. Dubbed methicillin-resistant Staphylococcus aureus (MRSA), it was one of the first germs to be resistant to all but the most powerful drugs.
Staph bacteria are generally harmless unless they enter the body through a cut or other wound. In older adults and people who are ill or have weakened immune systems, ordinary staph infections can cause serious illness. Staph infections, including MRSA, occur most frequently among persons in hospitals and healthcare facilities, such as nursing homes and dialysis centers, who have weakened immune systems; however, in the 1990s, a type of MRSA began appearing in the wider community. Today, that form of staph, known as community-associated MRSA, or CA-MRSA, is responsible for many serious skin and soft tissue infections and for a serious form of pneumonia. If not treated properly, MRSA infection can be fatal.
MRSA infections in the community are usually manifested as skin infections, such as pimples and boils. These CA-MRSA infections can occur in otherwise healthy people, and commonly occur among athletes who share equipment or personal items including towels and razors. In fact, from 2000 to present, there have been several reported outbreaks of CA-MRSA affecting high school and professional athletic teams. This epidemic among athletes is aided by the fact that MRSA grows very rapidly in warm, moist areas such as gyms and gym locker rooms. Common cuts and abrasions such as those frequently occurring in football and baseball now pose significant threats due to the possibility of an MRSA infection.
MRSA infections are spreading rapidly in the United States and worldwide. According to the Center for Disease Control and Prevention (CDC), the proportion of infections that are antimicrobial resistant has been growing. In 1974, MRSA infections accounted for two percent of the total number of staph infections; in 1995 it was 22%; and in 2004 it was nearly 63%. Additionally, recent research has suggested that 30-50% of the population carries MRSA colonies on their bodies all the time, helping to facilitate the spread of infection.
Vancomycin is one of the few antibiotics still effective against hospital strains of MRSA infection, although the drug is no longer effective in every case. Several drugs continue to work against CA-MRSA, but CA-MRSA is a rapidly evolving bacterium, and it may be a matter of time before it, too, becomes resistant to most antibiotics.
Chlorhexidine is a chemical antiseptic, and it combats both gram positive and gram negative microbes. It is bacteriostatic, hampering the growth of bacteria, and bacteriocidal, killing bacteria. It is often used as an active ingredient in mouthwash designed to kill dental plaque and other oral bacteria. Chlorhexidine also has non-dental applications. For example, it is used for general skin cleansing, as a surgical scrub, and as a pre-operative skin preparation. Chlorhexidine is typically used in the form of acetate, gluconate, or hydrochloride, either alone or in combination with other antiseptics such as cetrimide.
The use of chlorhexidine in wound irrigation applications has been previously described. See, for example, U.S. Published Application No. 2011-0288507A and U.S. Published Application No. 2011-0097372A, both of which are incorporated herein, by reference, in their entireties.